Combination wheeled and crawler type support for vehicles



Dec. 15, 1959 J, GATES ETAL 2,917,120

COMBINATION WHEELED AND CRAWLER TYPE SUPPORT FOR VEHICLES Original Filed Dec. 17, 1954 INVENTORS. Jose/=4 fiAeoLa GA T65 DALE GA 7'55 2,917,120 Patented Dec. 15, 1959 COMBINATION WHEELED AND CRAWLER TYPE SUPPORT FOR VEHICLES Joseph Harold Gates, Hollywood, Calif., and Dale Gates, Milroy, Ind.

Original application December 17, 1954, Serial No. 475,879, now Patent No. 2,844,413, dated July 22, 1958. Divided and this application September 16, 1957, Serial No. 684,299

8 Claims. (Cl. 180-936) The present invention has to do with a combination wheeled and crawler type supported for vehicles and is particularly concerned with a powered support therefor, it being a general object of the invention to provide a. simple, practical, improved support adapted for use in the handling or moving of cargo or loads of various kinds, whether over flat surfaces or up or down stairs or like obstacles.

This is a divisional application of application for Letters Patent Serial No. 475,879, filed December 17, 1954, and issued as Patent No. 2,844,413 entitled Power Attachment for Hand Trucks and the Like.

Ordinary wheel supported cargo handling trucks have long been used and structures for such devices have been proposed or provided to facilitate movement up or down stairs, or the like. Structures of the character under consideration are, for the most part, such as to require considerable skill and care in their operation, as well as considerable manual effort.

It is an object of this invention to provide a powered crawler type support for a hand truck which is such that it can be readily operated or rolled over an ordinary surface, such as a floor, in the course of ordinary handling of a load, and which is such that it can, without any variation whatsoever, be operated either up or down stairs or over obstacles as circumstances require.

It is another object of this invention toprovide a cargo carrier or hand truck of the character under consideration wherein two powered supporting means are related to each other and are adapted to be selectively employed.

Another object of the invention is to provide a hand truck of the character referred to wherein there is a tractor or crawler type support and a wheeled support,

which supports are related so that either can be readily engaged or selected for operation as circumstances require.

It is still another object of this invention to provide a powered support for a cargo carrier or hand truclc wherein a tractor type tread or support is power driven and which is of reliable and sturdy construction.

The various objects and features of our invention will be fully understood from the following detailed description of a typical preferred form and application of our invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a View showing a typical hand truck employing the powered support of the present invention as it 'is used or operated to negotiate stairs. Fig. 2 is a plan view of the support of the present invention showing it applied to the frame of a hand truck. Fig. 3 is a view taken as indicated by line 3-3 on Fig. 2. Fig. 4 is an enlarged view of a portion of the tractor type support. Fig. 5 is a sectional view through the tractor type support taken as indicated by line 55 on Fig. 4, and Fig. 6 is a perspective view of one of the elements of the support that we have provided.

The hand truck may include, generally, a framekA which is an elongate rigid unit and the powered support of the present invention which includes a crawler type support B, and a wheeled support C. The supports B and C are power driven by means of a suitable prime mover or power mechanism D and are related to each other so that either support may be operably engaged with the supporting surface as circumstances require. The crawler type support B is carried by the frame A and is driven by the prime mover D, while the wheel support C is carried by and driven by elements of the support B.

The frame A may vary widely in form and construction and is essentially an elongate rigid unit. As illustrated, the frame A may be a fabricated structure and includes, generally, top rails 10, bottom rails 11, and end plate 12 at the forward end of the frame and suitable braces 16.spacing the rails 10 and 11. A top platform 14 is carried by the top rails 10 and various other parts may be incorporated incidental to those mentioned in order to complete the frame A as desired. In the particular case illustarted, braces 15 extend transversely of the frame between the rails 10 and 11 at the sides thereof, with the result that the general frame construction is established as a fixed rigid unit. Elongate runners 15' are provided at the bottom of the frame A adapted to cooperate with and support the lower portion 30 of the support B hereinafter described.

The crawler type support B is power driven and involves, generally a tread unit 20 at each side of the frame A. The tread units 20 are alike and each includes a front sprocket 21, a rear sprocket 22 and intermediate drive sprocket 23, and a continuous flexible tread 24. The sprockets 21, 22, and 23 are rotatably carried in suitable bearings 25-, 26, and 27, respectively, provided on the frame A so that the lower portion 30 of the tread 24 is straight and in a plane substantially parallel with the top of the frame A. In practice, the sprockets 21 and 22 are relatively small in diameter, while the sprocket 23 is rather large in diameter. The sprocket 23 is located intermediate the sprockets 21 and 22, preferably near the forward end of the frame A adjacent the sprocket 21. It will be apparent that the said lower portion 30 of the tread has supporting faces that lie in a plane parallel to a line that extends between the lowermost peripheral portions of the sprockets 22 and 23, and that by providing a relatively large drive sprocket 23 the tread 24 wfill have substantial engagement with the periphery there- 0 It is a feature of this invention to locate the sprocket 21, which is smaller in diameter than the sprocket 23,

on a center so located that the forward leading portion 3 1 of the tread 24 is angularly related to the lower portion 30 thereof. That is, the lowermost peripheral portion of the sprocket 21 is located above the plane of the portion 30 so that the leading portion 31 extends forwardly and upwardly from the periphery of the drive sprocket 23 to the periphery of the sprocket 21 and has supporting faces that lie in a plane inclined relative to the above specified plane of the portion 30.

The drive sprockets 23 of the two units 20 are on a common axis and are driven by a drive shaft 32 which extends transversely of the frame A and which is carried in the bearings 27.

The wheeled support C is power driven and includes, generally, two like wheels 35, one at each side of the frame A. The wheels 35 are carried by and are driven by the sprockets 21 and in accordance with the invention, are of substantially large diameter. In practice, the Wheels 35 are of such diameter that the periphery of the tire portions 36 thereof are radially outward of treads 24 as they extend around sprocket 21 and to exr 3 tend below' the plane of the portion 31 of the treads 24 above described. However, the diameter of the wheels 35 is limited so that the periphery of the tire portions 36 thereof occur above the plane of the portion of the treads 24 when the structure is positioned as shown in Fig. 3. Thus, the wheels will normally clear the ground or floor but when the frame A is raised to lift the crawler type support B the frame will become supported solely by the wheeled support C.

The prime mover D may be an electric motor and gear unit 40 powered through a cable 41 under control ofa reversing switch 42. or the like.

The present invention is characterized by the continuous flexible treads 24, above referred to, each of which involves a chain 45 engageable over the sprockets 21, 22 and 23, a series of tire units or pads 46 carried by the chain 45 and means X coupling the tire units 45 to the chain 45. The sprockets 21, 22 and 23 are provided with annular series of circumferentially spaced teeth, in which case the chain 45 is endless and may be a roller chain or the like, having a continuous series of roller pins 47 joined by links 48. At suitable intervals, preferably equidistant intervals, the links of the chain 45 are provided with laterally projecting ears 4-9 located at the outer face of the chain 45. As shown, the ears 49 occur at each side of the chain and have fastener opening 50 at each side of the chain 45 to receive the coupling means X above referred to.

The tire units or pads 46 are provided at intervals along the chain 45 and are secured thereto by the coupling means X hereinafter described, and each involves a block 53 of material, such as rubber or the like. It will be apparent that the hardness of the material forming the block 53 may be varied as circumstances require, depending upon the cushioning effect desired. The block 53 is essentially a rectangular solid and has a bottom face 54, a top face 55, a front face 56, a rear face 57 and end faces. As shown, the block 53 is chamfered, or beveled, where the faces 55 and 56 converge providing a forwardly inclined face 6i}, and is chamfered, or beveled, Where the faces 55 and 57 converge providing a rearwardly inclined face 61. The inclined faces 66 and 61 may be serrated as shown in connection with the face at to provide for better gripping or traction if so desired.

The means X for coupling the tire units or pads 46 to the chain 45' involves a base 65 which is, in practice, molded in or integrally combined with the block'53. The base 65 may be formed of sheet metal adapted to be bonded to or vulcanized to the block 53 and involves a fiat plate section 66 and upstanding flanges. As shown, the section 66 has an outer face 68 flush with the bottom face 54 of the block 53 and has a forward flange 69 and a rear flange 70. The flanges 69 and 7t) are spaced a substantial distance inwardly from the front and rear faces 56 and 57, respectively.

In accordance with the present invention the flanges 69 and 7% are provided with apertures 71 for passing bodies of material forming the block 53 so that bodies of material molded or integrally formed with the block 53 pass through the apertures 7i. In practice we pro vide a plurality of apertures 71' in each flange so that they occur in an elongate series (see Fig. 6 of the drawings}.

In order to secure the tire units or pack 46 to the chain 45 a pair of spaced openings 56; are provided in the base 65, which openings are adapted to align with the spaced openings 50 in the ears 49. Suitable fasteners stl-may be applied to the openings in order to secure the units 45 in position. As shown, the fasteners 89 may be rivets, or the like, in which case access passages 81 are formed in the block 53 to accommodate the driving tool of a rivet gun, or the like.

From the foregoing it will be apparent that we have provided an extremely simple and practical powered support for a hand truck, or like vehicle. With the crawler type support B and the wheel support C related to each other as above described, it is a simple matter to selectively operate the vehicle on either of the supports without the manipulation of any levers or the like.

It will be observed that the sprocket 21 is considerably smaller in diameter than the sprocket 23 to the end that he tread units 253 operate at slow speed, for example 12 feet per minute, while the wheels 35 operate at a higher speed, for example 30 feet per minute. Therefore, bylifting the tread units 26 off the ground or floor the vehicle is supported by the Wheels 35 to be advanced at high speed, or by lowering the tread units 20 into engagement with the ground or floor (see Fig. 3) the wheels 35 are lifted clear of the ground and the vehicle is advanced at slow speed. in order to ascend stairs the lower portion 30 of the tread units 2d are employed as shown in Fig. l, and as the portion 31 of the tread units approach the highest step, the end of the vehicle opposite the end at portion 31 is lifted whereby the wheels 35 are brought into supporting engagement. Since the wheels 35 move faster than the tread units 20 the said wheels may be employed to gain desired additional traclion in order to move onto the higher level or floor. Further, the wheels 35 afford smooth rolling contact at the foreward end of the vehicle. it will also be apparent that the series of blocks 53 on the tread units 26 engage the corners or" the stairs so that the hand truck is propelled upwardly or downwardly as desired in a positive and reliable manner.

Having described only a typical preferred form and application of our invention, we do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims:

Having described our invention, We claim:

1. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of said units including, a front sprocket, a rear sprocket and an intermediate sprocket, said sprockets supporting a continuous flexible tread, the tread extending between the lower peripheries of the intermediate'and rear sprockets and with supporting faces in a substantially horizontal plane and the tread extending between the lower peripheries of the intermediate and front sprockets and with supporting faces in a forwardly inclined plane, and a wheeled support at the front sprockets with a wheel at each side of the vehicle.

2. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of said units including, a front sprocket, a rear sprocket and an intermediate sprocket, said sprockets supporting a continuous flexible thread, the tread extending between the lower peripheries of the intermediate and rear sprockets and with supporting faces in a substantially horizontal plane and the tread extending between the lower peripheries of the intermediate and front sprockets and with supporting faces in a forwardly inclined plane, and a wheeled support at the front sprockets with a wheel at each side of the vehicle and each having a periphery spaced above the supporting faces of the tread in said first mentioned plane.

3. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of said units including, a front sprocket, a rear sprocket and an intermediate sprocket, said sprockets supporting a continuous flexible tread, the tread extending between the lower peripheries of the intermediate and rear sprockets and with supporting faces in a substantially horizontal plane and the tread extending between the lower peripheries of the intermediate and front sprockets and with supporting faces in a forwardly inclined plane, and a wheeled support at the front sprockets with a wheel at each side of the vehicle and each having a periphery of greater radius than that of the tread carried at the front sprocket.

4. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of said units including, a front sprocket, a rear sprocket and an intermediate sprocket, said sprockets supporting a continuous flexible tread, the tread extending between the lower peripheries of the intermediate and rear sprockets and with supporting faces in a substantially horizontal plane and the tread extending between the lower peripheries of the intermediate and front sprockets and with supporting faces in a forwardly inclined plane, and a wheeled support at the front sprockets with a wheel at each side of the vehicle and each having a periphery of greater radius that that of the tread carried at the front sprocket and said peripheries being spaced above the supporting faces of the tread in said first mentioned plane.

5. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of said units including, a front sprocket, a rear sprocket and an intermediate sprocket, said sprockets supporting a continuous flexible tread, the front sprocket being smaller in diameter than the intermediate sprocket, and a wheeled support at the front sprockets with a Wheel at each side of the vehicle and each having a periphery spaced above the supporting faces of the tread at the intermediate sprockets.

6. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of said units including, a front sprocket, a rear sprocket and an intermediate drive sprocket, said sprockets supporting a continuous flexible tread, and a wheeled support at the front sprockets with a wheel at each side of the vehicle and carried and driven by the front sprockets, the tread extending between the lower peripheries of the drive sprocket and rear sprocket and with supporting faces in a substantially horizontal plane and extending between the lower peripheries of the drive sprocket and front sprocket and with supporting faces in a forwardly inclined plane, the periphery of each wheel being spaced above the supportingfaces of the tread in said first mentioned plane.

6 7. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of 7 said units including, a front sprocket, a rear sprocket and an intermediate drive sprocket, said sprockets supporting a continuous flexible tread, and a wheeled support at the front sprockets with a wheel at each side of the vehicle and carried and driven by the front sprockets, the tread extending between the lower peripheries of the drive sprocket and rear sprocket and with supporting faces in a substantially horizontal plane and extending between the lower peripheries of the drive sprocket and front sprocket and with supporting faces in a forward inclined plane, the periphery of each wheel being of greater radius than that of the tread carried at the front sprocket.

8. A vehicle support including, a crawler type support with a tread unit at each side thereof, each of said units including, a front sprocket, a rear sprocket and an intermediate drive sprocket, said sprockets supporting a continuous flexible tread, and a wheeled support at the front sprockets with a wheel at each side of the vehicle and carried and driven by the front sprockets, the thread extending between the lower peripheries of the drive sprocket and rear sprocket and with supporting faces in a substantially horizontal plane and extending between the lower peripheries of the drive sprocket and front sprocket and with supporting faces in a forwardly inclined plane, the periphery of each wheel being of greater radius than that of the tread carried at the front sprocket and said peripheries being spaced above the supporting faces of, the tread in said first mentioned plane.

References Cited in the file of this patent UNITED STATES PATENTS 281,859 Fox July 24, 1883 970,787 Brown Sept. 20, 1910 1,465,676 Malone 'Aug. 21, 1923 2,214,311 Stevens Sept. 10, .1940 2,597,532 Richardson May 20, 1952 2,770,310 Gates Nov. 13, 1956 

